Levelling blocks and ramps
How many leveling blocks does your trailer actually need?
Interlocking leveling blocks solve a problem that looks cosmetic and is not. A trailer sitting even a few degrees out of level side to side will not run an absorption-style refrigerator correctly, because that design depends on gravity to circulate the ammonia solution inside it, and enough tilt stops that circulation regardless of how good the unit is. Front to back level matters for a completely different reason: grey and black tank sensors and the tank outlets themselves are positioned assuming a level trailer, and towing or parking nose-high or nose-low drains them unevenly and can leave standing waste in a tank that reads empty.
Interlocking blocks earn their keep over loose lumber for one specific reason: they are engineered to resist lateral load. A stack of scrap wood under a trailer wheel or a jack can squirt out sideways the moment weight settles unevenly across it, which is exactly the moment you do not want the support moving. A modular block system with an interlocking pattern on multiple sides stays put under the same load because the blocks are keyed into each other rather than simply stacked.
How many blocks you need depends on axle count more than anything else. A single axle trailer needs one stack, built to whatever height the low side of the site requires. A tandem axle trailer needs the same stack height under both tires on each side, which roughly doubles the block count compared with a single axle trailer on the same slope. A heavy fifth wheel jack sometimes needs a wider base rather than just a taller one, which is a different requirement again.
On this page
- Beginner: the correct pack size for a single axle trailer or a mild slope
- Intermediate: double the blocks for a tandem axle trailer or a genuinely bad site
- Expert: a wider base for a heavy fifth wheel jack, not just a taller one
- How many blocks does your axle configuration actually need?
- Blocks compared by piece count and rated capacity
- The full leveling process is its own guide
Beginner: the correct pack size for a single axle trailer or a mild slope
This is the category standard pack size, and it is genuinely enough rather than a starter kit you will immediately outgrow on most single axle trailers.
Lynx Levelers, 11 pack with cap
$33.18Eleven interlocking pieces including a cap, rated to withstand up to 40,000 lb combined and stacking into a pyramid that will not squirt out sideways under load.
Best for: A single axle trailer, or a tandem axle trailer on a site that is only mildly out of level.
Check price on AmazonIntermediate: double the blocks for a tandem axle trailer or a genuinely bad site
This is the buy-once pick once a second axle or a consistently sloped site is in the picture, because running out of blocks mid-stack on a real trip is the actual failure mode this tier avoids.
Lynx Levelers, 22 pack with two caps
$59.99Twenty two interlocking pieces with two caps and two storage bags, effectively double the smaller pack, which is what a tandem axle trailer actually needs once both tires and the tongue jack are all being built up on a bad site.
Best for: A tandem axle trailer, or any site that reliably turns out to be worse than it looked from the truck.
Check price on AmazonExpert: a wider base for a heavy fifth wheel jack, not just a taller one
Camco FasTen RV Leveling Blocks, 10 pack
$60.03Interlocks on all four sides rather than two, which lets a stack be built wider as well as taller, engineered for use with hydraulic, tongue, stabiliser and fifth wheel jacks specifically rather than only under a tire.
Best for: Building a wide, stable base under a heavy fifth wheel landing gear jack, where a tall narrow stack is the wrong shape for the load.
Check price on AmazonWho should not buy this tier: A small single axle trailer on mostly flat sites. The quad-grid four-sided interlock earns its price specifically when a stack needs width as well as height under a heavy jack, and that problem does not exist on a light trailer with a small tongue jack footprint. The Lynx 11-pack above is plenty in that case.
How many blocks does your axle configuration actually need?
A tandem axle trailer needs roughly double the blocks of a single axle trailer on the same slope, because both tires on each side need matching stack height.
Rule of thumb Widely taught towing convention rather than a published specification. It is a good starting point and it is not a rating.
| Trailer type | What drives the block count | Pack that typically covers it |
|---|---|---|
| Single axle travel trailer, mild slope | One stack under the low tire, plus the tongue jack | The 11-pack has real headroom |
| Tandem axle travel trailer, bigger slope | Matching stack height under both tires on the low side | The 22-pack, roughly double the smaller trailer |
| Fifth wheel with a single heavy landing gear jack | A wider base rather than a taller one, to spread the load | A quad-grid interlock built for width as well as height |
This is a practical rule of thumb based on axle geometry rather than a published engineering standard. The slope of your own site is the real variable and can require more or fewer blocks than this table suggests.
Blocks compared by piece count and rated capacity
The Lynx Levelers, 22 pack with two caps carries double the pieces of the Lynx Levelers, 11 pack with cap for $59.99, and both share the same published 40,000 lb combined rating.
Published standard A published, traceable figure: a standards body, a federal regulation or a manufacturer specification states it.
| Blocks | Piece count | Rated combined load | Interlock sides | Price |
|---|---|---|---|---|
| Lynx Levelers, 11 pack with cap | 11, including cap | 40,000 lb | 2 | $33.18 |
| Lynx Levelers, 22 pack with two caps | 22, including two caps | 40,000 lb | 2 | $59.99 |
| Camco FasTen RV Leveling Blocks, 10 pack | 10 | Not published as a single combined figure | 4 | $60.03 |
Manufacturers publish these combined load figures for the interlocked system itself. Your trailer axle rating and jack rating are the separate limits that actually govern how much weight is on the blocks.
The full leveling process is its own guide
Getting a trailer level, front to back and side to side, before the jacks or stabilisers ever go down is a process worth doing right rather than summarizing twice. Our leveling blocks answer the question of how many blocks to own; a bubble level mounted on the trailer frame answers whether you have actually hit level once the blocks are under the tires. See our full walkthrough on how to level a trailer for towing for the step by step process, from checking the site to confirming both axes.
How we chose
We did not test this hardware in person and we never claim to. Picks are researched from manufacturer specification sheets, published towing standards, and the recurring themes in verified owner reviews. Every pick is matched to a real gross trailer weight rating, a real tongue or pin weight rating, a real receiver size or a real load index rather than to a price bracket, and it is placed in the tier where its published capability actually belongs. We rejected the unbranded flood that dominates the search results in several of these categories, because a weight distribution hitch, a brake controller, a trailer tire and a set of safety chains are all parts whose failure puts a loose trailer on a public road. Where a figure is towing convention rather than a published standard we label it that way, and where a manufacturer does not publish a figure we leave it out instead of estimating it.
Frequently asked questions
How many leveling blocks do I need for a tandem axle trailer?
Roughly double what a single axle trailer needs on the same slope, because both tires on the low side have to sit on matching stack heights rather than just one. The 22-piece Lynx pack is built for exactly this case, where the 11-piece pack is more likely to run short mid-stack on a genuinely uneven site.
Why does side to side level matter for an RV refrigerator?
Absorption-style RV refrigerators, the kind that can also run on propane, rely on gravity to circulate an ammonia solution through the cooling unit. Enough side to side tilt interrupts that circulation regardless of how well the unit is otherwise working, which is why manufacturers publish a maximum allowable tilt and why getting level matters even when the trailer feels stable to walk around in.
Can I use lumber instead of interlocking leveling blocks?
You can, but loose lumber lacks the interlocking pattern that keeps a manufactured block system from shifting sideways once weight settles unevenly across the stack. That lateral movement is the actual failure mode, not the wood itself being too weak vertically. Interlocking blocks cost little more and solve the specific problem lumber does not.
Do I need different leveling blocks for a fifth wheel than a travel trailer?
Often yes, though not because of weight alone. A heavy fifth wheel landing gear jack frequently needs a wider base rather than a taller one to spread the load safely, which is what a four-sided interlocking design like the Camco FasTen is built for. A travel trailer tire stack more commonly just needs height, which the standard Lynx blocks handle well.
How high can leveling blocks be safely stacked?
Follow the manufacturer's published maximum stack height rather than guessing. The Camco FasTen blocks, for example, specify a maximum stack of four and a half inches. Stacking beyond a published limit reduces the lateral stability the interlocking design exists to provide, which defeats the reason to use them over loose lumber in the first place.
Do leveling blocks replace the trailer's corner stabiliser jacks?
No. Leveling blocks get the trailer frame level under the tires or the tongue jack before anything else happens. Corner stabiliser jacks come down afterward to reduce bounce while walking inside a parked trailer, and they are a separate step that does not correct for an unlevel trailer on its own.
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Researched, not professional advice. This page is compiled from published standards, manufacturer towing guides and product specifications, and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are towing convention rather than published standards, and they are labelled that way wherever they appear. Nothing here overrides your own ratings. Work your payload sum before your tow rating, because payload is the limit that actually binds on most half ton trucks and nearly every SUV. Load a conventional trailer to 10 to 15 percent tongue weight and a fifth wheel to 15 to 25 percent pin weight, and never lighter: a tail heavy trailer is what starts sway. Weigh the rig loaded rather than trusting a brochure dry weight. A weight distribution hitch and a set of air bags both restore ride height and control, and neither one raises a single rating. Trailer brakes are required by state law above a threshold that varies by state, and a breakaway battery that has quietly gone flat is the normal condition of most trailers on the road.